1. Field of the Invention
This invention relates to a heat processing apparatus of a substrate.
2. Description of the Related Art
In a process of photo resist processing in fabricating a semiconductor device, various heat processings are operated such as heat processing after coating a resist solution onto a surface of a semiconductor wafer (hereinafter referred to as xe2x80x9cwaferxe2x80x9d) (prebaking), heat processing after an exposure of a pattern (post-exposure baking) and so on.
These heat processings are usually operated in heat processing apparatuses. The heat processing apparatus has a circular-shaped heating plate 150 to mount and heat the wafer W thereon in a process container (not-shown) as shown in FIG. 13 and FIG. 14, and a heater (not-shown) is embedded in the heating plate 150. The heating plate 150 is usually supported by an annular-shaped supporting member 151 which is excellent in heat insulting property and supports a lower surface of a periphery thereof, and the supporting member 151 has a stepped portion 151a which surrounds an outer peripheral surface of the heating plate 150 for positioning the heating plate 150. Further, the supporting member 151 is supported by a supporting table 152 which supports a lower surface of the supporting member 151, and the supporting member 151 is fixed to the supporting table 152 by a plurality of bolts 153 which penetrate through the stepped portion 151a in a vertical direction.
The heat processing of the wafer W is operated by thuss-structured apparatus at a predetermined temperature, but the temperature of the heating plate 150 may be changed in changing a recipe of the process and the like. In the case like this, the heating plate 150 is usually cooled temporarily. At this moment, the supporting member 151 which is expanded outwardly by heat of the heating plate 150 when being heated is cooled to shrink inwardly.
However, as described above, since the supporting member 151 is fixed to the supporting table 152 by the bolts 153, areas which are not fixed by the bolts 153 (the diagonally shaded areas in FIG. 15) as shown in FIG. 15 are expanded more than fixed areas when it is heated. Thereafter, when it is cooled, the areas which are not fixed by the bolts 153 shrink to these original positions, but at the areas which are fixed by the bolts 153, parts 151a of the supporting member 151 which are placed on inner sides of the bolts 153 shrink inwardly, as shown in FIG. 16. Therefore, there are cases in which the heating plate 150 is partially compressed by the shrinking of the parts 151a of the supporting member 151 to distort its shape. In this case, harmful effects such as uneven temperature on a surface of the heating plate 150 occur, and there is a possibility that the heating of the wafer W is not operated preferably.
The present invention is made in view of the above circumstances, and its object is to prevent an occurrence of distortion of a heating plate by being partially compressed, even when a supporting member shrinks when it is cooled in a heat processing apparatus of a substrate.
To attain the above-mentioned object, according to a first aspect of the present invention, the present invention is an apparatus for operating heat processing to a substrate, comprising a heating plate to mount and heat the substrate thereon, a supporting member to support a lower surface of a periphery of the heating plate, and a supporter to support the supporting member, wherein the supporting member has a stepped portion to surround an outer peripheral surface of the heating plate, wherein the supporting member is fixed to the supporter by a fixing member penetrating through the stepped portion in a vertical direction, and wherein a peripheral surface of the fixing member on a side to be opposed to the outer peripheral surface of the heating plate is exposed toward a heating plate side.
According to another aspect of the present invention, the present invention is an apparatus for operating heat processing to a substrate, comprising a heating plate to mount and heat the substrate thereon, a supporting member to support a lower surface of a periphery of the heating plate, and a supporter to support the supporting member, wherein the supporting member has a stepped portion to surround an outer peripheral surface of the heating plate, wherein the supporting member is fixed to the supporter by a fixing member penetrating through the stepped portion in a vertical direction, and wherein the fixing member is provided between an inner peripheral surface of the stepped portion and the outer peripheral surface of the heating plate.
According to still another aspect of the present invention, the present invention is an apparatus for operating heat processing to a substrate, comprising a heating plate to mount and heat the substrate thereon, a supporting member to support a lower surface of a periphery of the heating plate, and a supporter to support the supporting member, wherein the supporting member has a stepped portion to surround an outer peripheral surface of the heating plate, wherein the supporting member is fixed to the supporter by a fixing member penetrating through the stepped portion in a vertical direction, and wherein the fixing member is adjacently provided outside the outer peripheral surface of the heating plate. Incidentally, providing the fixing member adjacently outside the outer peripheral surface of the heating plate means that a part of the supporting member does not exist between the fixing member and the outer peripheral surface of the heating plate as its consequence.
According to yet another aspect of the present invention, the present invention is an apparatus for operating heat processing to a substrate, comprising a heating plate to mount and heat the substrate thereon, a supporting member having a stepped portion to surround an outer peripheral surface of the heating plate, to support a lower surface of a periphery of the heating plate, and a supporter to support the supporting member, the supporting member including a through-hole penetrating in a horizontal direction from an outside of the stepped portion toward an inside thereof, and the apparatus further comprising a fixing member being fixed to the supporting member by penetrating through the through-hole to fix the heating plate by pressing its outer peripheral surface.
According to the present invention, by providing the fixing member with its peripheral surface exposed to the heating plate side, the part of the supporting member does not exist between the outer peripheral surface of the heating plate and the fixing member, contrary to the conventional art, and even when the heating plate is cooled, the part of the supporting member does not shrink toward the heating plate side, contrary to the conventional art. Thus, it is prevented that the part of the supporting member partially compresses the heating plate to distort the heating plate.
According to the present invention, by providing the fixing member between the outer peripheral surface of the heating plate and the inner peripheral surface of the stepped portion, the supporting member does not exist between the fixing member and the outer peripheral surface of the heating plate, and even when the heating plate is cooled, the part of the supporting member does not shrink toward the heating plate side, contrary to the conventional art. Thus, it is prevented that the part of the supporting member partially compresses the heating plate to distort the heating plate.
According to the present invention, by adjacently providing the fixing member outside the outer peripheral surface of the heating plate, the outer peripheral surface of the heating plate is not partially compressed by the shrinking of the supporting member. Therefore, even when the heating plate is cooled, the heating plate is prevented from distorting.
According to the present invention, by providing the fixing member horizontally, expansion/contraction of the supporting member which extends mainly in the horizontal direction by the heat is not restrained by the fixing member, and hence it is prevented that the supporting member partially shrinks to distort the heating plate partially, contrary to the conventional art. Moreover, the fixing member holds the outer peripheral surface of the heating plate, so that the heating plate is fixed to a predetermined position and an erroneous deviation thereof is prevented.
In this invention, it is preferable to provide a collar to an outer periphery of the fixing member. By attaching the collar to the fixing member, it is prevented that the fixing member contacts the supporting member directly, thereby inhibiting harmful effects due to the heat of the supporting member and the heating plate, for example, an effect of losing the strength of the fixing member due to fatigue or the like. Furthermore, it is prevented that the fixing member and the supporting member or the heating plate contact directly to generate particles by friction thereof.